P2123
DTC P2123: Accelerator Pedal Position Sensor (main) Circuit High InputAccelerator Pedal Position Sensor (main) Circuit:
CIRCUIT OPERATION
- A 5-volt power supply is applied on the accelerator pedal position sensor (main) power terminal (terminal No. 1) from the ECM (terminal No. 75).
- A voltage that is according to the accelerator opening angle is sent to the ECM (terminal No. 74) from the accelerator pedal position sensor (main) output terminal (terminal No. 3).
- The ground terminal (terminal No. 2) is grounded with ECM (terminal No. 76).
TECHNICAL DESCRIPTION
- The accelerator pedal position sensor (main) outputs voltage which corresponds to the accelerator pedal depression.
- The ECM checks whether the voltage is within a specified range.
DESCRIPTIONS OF MONITOR METHODS
Accelerator pedal position sensor (main) output voltage is out of specified range.
MONITOR EXECUTION
Continuous
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
- Not applicable
Sensor (The sensor below is determined to be normal)
- Not applicable
DTC SET CONDITIONS
Logic Flow Chart
Logic Flow Chart:
Check Condition
- Ignition switch is "ON" position.
Judgement Criterion
- Accelerator pedal position sensor (main) output voltage should be 4.8 volts or higher for 0.3 second.
FAIL-SAFE AND BACKUP FUNCTION
- Throttle opening degree is restricted.
- Throttle opening degree position is in default position if accelerator pedal position sensor (sub) fails.
OBD-II DRIVE CYCLE PATTERN
None.
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Accelerator pedal position sensor failed.
- Open accelerator pedal position sensor (main) circuit, harness damage or connector damage.
- ECM failed.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A
STEP 1. Using scan tool MB991958, check data list item 11: Accelerator Pedal Position Sensor (main).
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Set scan tool MB991958 to the data reading mode for item 11, Accelerator Pedal Position Sensor (main).
- Output voltage is between 0.9 and 1.1 volts when foot is released from accelerator pedal.
- Output voltage is 4.0 volts or higher when accelerator pedal is fully depressed.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES : It can be assumed that this malfunction is intermittent.
NO : Go to Step 2.
STEP 2. Check harness connector C-01 at accelerator pedal position sensor for damage.
Q: Is the harness connector in good condition?
YES : Go to Step 3.
NO : Repair or replace it. Then go to Step 8.
STEP 3. Check the continuity at accelerator pedal position sensor harness side connector C-01.
1. Disconnect the connector C-01 and measure at the harness side.
2. Measure the continuity between terminal No. 2 and ground.
- Continuity (2 ohms or less)
Q: Does continuity exist?
YES : Go to Step 7.
NO : Go to Step 4.
STEP 4. Check harness connector B-10 at ECM for damage.
Q: Is the harness connector in good condition?
YES : Go to Step 5.
NO : Repair or replace it. Then go to Step 8.
STEP 5. Check for open circuit and harness damage between accelerator pedal position sensor connector C-01 (terminal No. 2) and ECM connector B-10 (terminal No. 76).
Q: Is the harness wire in good condition?
YES : Go to Step 6.
NO : Repair it. Then go to Step 8.
STEP 6. Using scan tool MB991958, check data list item 11: Accelerator Pedal Position Sensor (main).
1. Turn the ignition switch to the "ON" position.
2. Set scan tool MB991958 to the data reading mode for item 11, Accelerator Pedal Position Sensor (main).
- Output voltage is between 0.9 and 1.1 volts when foot is released from accelerator pedal.
- Output voltage is 4.0 volts or higher when accelerator pedal is fully depressed.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES : It can be assumed that this malfunction is intermittent.
NO : Replace the ECM. When the ECM is replaced, register the ID code. Then go to Step 8.
STEP 7. Replace the accelerator pedal position sensor.
1. Replace the accelerator pedal position sensor.
2. Turn the ignition switch to the "ON" position.
3. After the DTC has been deleted, read the DTC again.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC P2123 set?
YES : Replace the ECM. When the ECM is replaced, register the ID code. Then go to Step 8.
NO : The inspection is complete.
STEP 8. Using scan tool MB991958, read the diagnostic trouble code (DTC).
1. Turn the ignition switch to the "ON" position.
2. After the DTC has been deleted, read the DTC again.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC P2123 set?
YES : Retry the troubleshooting.
NO : The inspection is complete.